https://developers.weixin.qq.com/miniprogram/dev/api/device/bluetooth-ble/wx.writeBLECharacteristicValue.html

蓝牙模块示例代码(demo)代码有误，wx.writeBLECharacteristicValue(Object object) 报错10004！！！

解决方法：如下 serviceId: this._deviceId, 改为serviceId: this._serviceId

wx.writeBLECharacteristicValue({
      deviceId: this._deviceId,
      serviceId: this._serviceId,
      characteristicId: this._characteristicId,
      value: buffer,
      success (res) {
        console.log('writeBLECharacteristicValue success', res.errMsg)
      }
    })